Pressure regulating valves of the aforementioned type serve to reduce a higher primary pressure at the primary connection to a lower secondary pressure at the secondary connection through the characteristics of the relief valve. However, valves of the aforementioned type do not have the capability of being directly controlled in response to variables other than the level of the secondary pressure. For example, it may be desirable to provide direct control of the pressure regulating valve in response to pressures in the system being regulated or the mechanical displacement of a load.
Accordingly, it is a principal object of the invention to provide a pressure regulating valve with a control connection for feedback of a controlled variable or quantity. Further objects of the invention are to provide a controlled connection wherein the controlled quantity may be a system pressure or a mechanical displacement, and to implement the pressure regulating valve in a system as a feedback control.